A blower mounted in a vehicle has a blower fan and a shroud. The blower fan supplies air to a radiator. The shroud supports the blower fan and defines an air passage extending from the radiator to the blower fan.
The blower is known to increase a volume of running wind supplied to the radiator in a manner that the shroud is configured to cover only a part of a radiator core so as to improve a cooling performance of the vehicle while moving at a high speed. On the other hand, another blower is known to force air blown by a blower fan to pass through an entirety of a radiator core by configuring a shroud to cover an entire surface of a radiator core, so as to improve a cooling performance of a vehicle while stopping and being in an idling condition.
Another blower is disclosed (e.g., in Patent Literature 1) to have a shroud that covers an entire surface of a radiator core. The shroud has an opening and a flap that opens and closes the opening by a ram pressure of the running wind of the vehicle. The blower is capable of opening and closing the opening by rotating the flap from the wall of the shroud toward an inside of the shroud.
According to the blower described in Patent Literature 1, the flap rotates by the ram pressure of the running wind passing through the radiator and opens the opening while the vehicle is moving. As a result, the running wind in a motor fan shroud can flow toward a vehicle rear side efficiently. In addition, the blower can cause air blown by a blower fan to pass through an entirety of the radiator while the vehicle is stopped and in an idling condition.